The Raisin River watershed (HUC 04100002) covers an area of approximately 1,175 square miles in southeastern Michigan. The hydrology of the watershed is dominated by the Raisin River, which flows for 120 miles through the area and serves as the primary source of surface water. The watershed experiences significant snowfall during winter months, with an average snowpack of 20-40 inches. Surface water in the Raisin River and its tributaries is used for drinking water supply, irrigation, and recreation. The watershed contains several reservoirs, including Lake Columbia, Lake Somerset, and Wamplers Lake, which serve as important sources of water for the surrounding communities. Climate trends in the Raisin River watershed have shown an increase in extreme weather events, such as heavy precipitation and flooding, which can impact the area's hydrology and water management strategies.